Clinical and non-clinical scientific studies of biological responses, and in particular, dermatological responses, are hindered when current methods or devices cannot detect weak responses or distinguish among multiple causes for an observed response. Such studies are further hindered when the response being studied occurs with relatively low and unpredictable frequency among the general population.
Spectroscopic data of metabolites from biological samples are complex, and visual inspection can only yield a small amount of the information available. A different technique, coined metabonomics by Jeremy Nicholson and mirrored after genomics and proteomics, has been developed to extract the maximum information from the complex spectra measured. Specifically, metabonomics is a quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modification (Lindon et al., Prog. NMR Spectrosc., 39:1 (2001)). What makes metabonomics potentially more powerful than either genomics or proteomics is that many disease states involve more than one gene or protein, but involve a finite number of metabolites. By studying spectroscopic data of small molecule metabolites from a biological sample, one can trace the levels of the metabolites of interest during the course of a disease state in comparison to a control sample. The dynamic and time-dependent profiles of the metabolites allow for the appraisal of treatments and, in some cases, can assist in diagnosis of a disease-state.
One particularly useful means of measuring metabolites in a biological sample is nuclear magnetic resonance (NMR). High field proton NMR spectra have been measured and compared for metabolite level differences between diseased subjects and control subjects, as well as for historical analyses of metabolite levels over a period of time for a disease. The spectra have been amassed in a database and can be used for comparison with future samples. Most applications of metabonomics have focused on blood and urine samples. There is now a large database of spectra of both urine and blood from subjects diagnosed with a wide range of diseases, such as the proprietary databases of Metabomatrix (London, UK), or annual reports such as, e.g., “Annual Reports on NMR SPECTROSCOPY” G. A. Webb, ed., Academic Press, volume 38: 1-88 (1999).
Little work has been done on the metabolites involved in skin conditions or on how those metabolites change during the course of a diseased or challenged state. Thus, there exists a need in the art to more clearly elucidate metabolites associated with skin conditions, and changes therein, and to provide methods of assessing efficacy of skin treatments. Such methods would be particularly useful where enhancing or ameliorating a response to a challenge is desirable. Methods of this type would also be useful when the response of interest needs to be studied under both highly controlled and poorly-controlled challenge scenarios.